Determinants of recurrent atrial flutter after cardioversion.

Eighteen male patients (mean age 59 years) who were electrically cardioverted for pure atrial flutter were retrospectively studied to determine those factors influencing the maintenance of regular sinus rhythm or reversion to atrial flutter. Six months after successful cardioversion, 10 patients (55%) had recurrent atrial flutter and eight patients (45%) were still in sinus rhythm. The two groups were not significantly different with respect to age, symptomatology, abnormalities on the 12 lead electrocardiogram (during sinus rhythm), or the administration of digoxin and a class Ia antiarrhythmic agent (after cardioversion). There was a trend for those patients with recurrent atrial flutter to have a higher incidence of underlying heart disease and previous episodes of atrial flutter than the non-recurrent group. There were statistically significant differences between the recurrent and non-recurrent groups with respect to echocardiographically determined left atrial size and left ventricular ejection fraction. Patients with a left atrial size greater than 45 mm or with an ejection fraction less than 45% were all at high risk for recurrent atrial flutter after successful cardioversion.